Electronic device manufacturers strive to produce a rich interface for users. Conventional electronic devices often provide visual and/or auditory feedback to communicate information to users. In some cases, kinesthetic feedback (such as active and resistive force feedback) and/or tactile feedback (such as vibration, texture, and heat) may also be provided to the user to enhance the user experience. Generally speaking, kinesthetic feedback and tactile feedback are collectively known as “haptic feedback” or “haptic effects.” Haptic feedback may be useful for providing cues to alert the user of specific events or to provide realistic feedback sensations to create a greater sensory experience. Haptic feedback can be used with common electronic devices and even devices used for creating a simulated or virtual environment.
Various haptic actuation technologies have been used in the past to provide vibrotactile haptic feedback to touch sensitive devices, such as touch screens. Known haptic feedback devices use electric actuators, such as Linear Resonant Actuator (“LRA”) devices and Eccentric Rotating Mass (“ERM”) devices. However, these actuators usually have very limited bandwidth to perform sufficiently in haptic applications.
Another conventional haptic feedback technology in touch sensitive devices is electro-active polymer (“EAP”) devices. One drawback of this technology, however, is that EAP-based actuators normally require thousands of volts of electricity to provide effects that are suitable for haptic applications.
Development of haptic feedback structures has led to smaller, more compact devices. As display screens having high definition have increased, so has the need for high definition haptic feedback.